What would happen in Freeway Pro? Just curious I never used the app.
The only thing in Blocs that may happen regarding interference, would be trying to use improper maligned HTML that it does not support, vs the clean HTML that it requires. Or perhaps using 3rd party CSS or JS that has namespace conflicts / specificity with Blocs CSS, using the wrong order in which 3rd party libraries are loaded, etc., typical issues even in standard development.
Overall however you should be fine, if you come across something let us know I would be interested regarding this and what would become an issue.
There is an abundance of commonly used open-source CSS and JS libraries that could be utilized, to allow further features via Blocs / Brics. Thus allowing the core of Blocs users whom don’t wish to interact with code directly, the ability to build more feature rich sites.
Time will tell, but I am sure more will come eventually @norm.